Refrigeration defrosting



March 12, 1963 M. H. DEVERY REFRIGERATION DEFROSTING Filed Aug. 14, 1961 2 Sheets-Sheet 2 INVENTOR. M/CHAH /1. @E1/EAW United dtates @arent 3,336,727 REFRIGERATN DEFRSTENG Michael H. Det/ery, Ambler, Pa., assigner, by mesne assignments, to Philco Corporation, Philadelphia, Pa., a corporation of Delaware Filed Aug. 14, 1961, Ser. No. 131,217 16 Claims. (Cl. 62-156) This invention relates to air moving apparatus and, while of broader applicability, is especially concerned with the use of novel air moving means for maintaining temperatures in refrigerator apparatus within predetermined useful limits to effect both food storage and economical defrosting of a cooling element of the refrigerator.

`It is known to defrost the cooling element or evaporator of a refrigerator by applying heat electrically thereto or by causing hot gaseous refrigerant to flow therethrough. Also, it is known merely to deenergize the refrigerating unit to allow the frost to melt from the evaporator over an extended period of time. However, the energy required to defrost by the first two methods undesirably increases operating costs of a refrigerating system, whereas the latter method is time-consuming to the detriment of stored frozen food, due to the excessively high temperatures resulting from the relatively long times required for defrosting by this method.

It is therefore a primary objective of the invention to provide improved means for effecting positive heat eX- change with the cooling element of refrigerator apparatus in both a defrosting and a refrigerating operation, said means overcoming the above mentioned difficulties.

It is also an object of my invention to provide improved air moving means operable to control the flow of air through different passages or z-ones, selectively.

In the achievement of the foregoing and other objectives, the invention comprises air moving means adapted for selective operation to effect flow of air through either of a pair of spaced air passage means, said air moving means including combined air impeller and damper elements so cooperatively disposed with the air passage means as, selectively, to provide for flow of air through one of such means to the exclusion of the other. The invention is featured by its particular utility in refrigerator apparatus comprising a lower temperature compartment, a higher temperature compartment, and a plenum chamber housin T a defrostable cooling element and air moving means, the latter in accordance with the invention being disposed and adapted to cause air flow between one of said compartments and said plenum chamber to cool such compartment, said cooling element being deenergizable cyclically at a lower temperature limit, and said air movinnr means being operable thereafter to effect flow of air from said higher temperature compartment over said cooling element to defrost the same.

The manner in which the foregoing objects and advantages may best be achieved will be understood from a Consideration of the following description taken in light of the accompanying drawing, in which:

FIGURE 1 is a somewhat diagrammatic elevational showing, partly in section, of refrigerator cabinet structure embodying the invention and showing an operational feature thereof;

'FIGURE 2 is a showing similar to FIGURE 1 and illustrating an additional operational feature of the invention;

:FIGURE 3 is an enlarged showing of the novel air moving apparatus seen in FIGURES 1 and 2;

FIGURE 4 is a view on a somewhat reduced scale and with parts broken away, looking in the direction of arrows 4 4 as applied to FIGURE 3; and

PEiGURES 5, 5A, 5B and 5C are somewhat diagrammatic showings of a novel electrical control system which is useful in carrying out the invention.

With more particular reference to the drawing, and first to FIGURES 1, 2, 3, and 4 a refrigerator cabinet 1t) having an outer shell 11 and an inner liner 12 spaced therefrom by suitable thermal insulation 13 comprises a freezer chamber or compartment 14 and an abovefreezing food storage chamber or compartment 15. For the sake of convenience, the showing of door structure for cabinet It) has been omitted, but it will be understood that such structure is provided in accordance with well known practice. Oompartments 14 and 1S are separated, one from the other, by a plenum chamber 16 within which there is disposed the evaporator coil 2t? of a refrigerator unit (FIGURE l) comprising a compressor 21, a condenser 22, and a capillary tube restrictor 23, connected in series flow circuit therewith by suitable conduits, in accordance with usual practice.

'Plenum chamber 16 is defined in part by a pair of walls 24 and 257 preferably of low thermal conductivity, and by liner 12. Wall 24 has a pair of openings 26 and Sil providing air flow communication between the food storage compartment 15 adjacent thereto and the plenum chamber 16. Similarly, wall 25 has a pair of openings 31 and 32 providing air -fiow communication between freezer compartment and plenum chamber 16.

The cooling element 2d, in this case a refrigerant evaporator, comprises plate means in which the tubing is preferably although not necessarily formed by embossing one metal plate of a relatively low mass metal, such for example as aluminum, with the desired refrigerant flow pattern and adhering thereto a second metal plate of like material by means of a brazing process, said plates being so cooperatively disposed as to provide a refrigerant flow path. Due to the lightweight material of the evaporator, it has such a low thermal mass as to accommodate its defrosting by natural cabinet heat leakage during the off period of the refrigerating cycle. Evaporator 20, in its plate form, extends intennediate walls 24 and 25 which form plenum chamber 16, and a baie structure or partition 33 is disposed in the same plane as the evaporator. Drain trough means 27 is provided below evaporator 2i), into which defrost water drains from the evaporator and is disposed of in the course of the above mentioned defrosting operation. The invention is particularly useful in enhancing the flow of heat into the evaporator as will be described in detail, in what follows.

Thermostatic control elements 34 and 35 are also disposed in the plenum chamber and include bellows and sensing bulb elements 55 and 60, respectively, disposed in thermal exchange with evaporator Ztl. Functions of control elements 34 and 35, in providing both the refrigerating and defrosting operations, will be explained in connection with FIGURES 5, 5A, 5B, and 5C.

With particular reference to FlGURE 3, the combined air moving and damper means 36 of the invention is disposed within plenum chamber 16 and comprises motor means 4d having a pair of separately energizable field windings 41 `and 42. A single armature or rotor 43 is axially aligned with the field windings and is adapted for selective axial movements, in the manner of a solenoid actuated core member, to become rotatably associated with either of motor field windings 41 and 42, whichever is energized. Armature 43 is supported upon a motor shaft 44 journalled, and 4also axially slidable, within suitable bracket means 45 and 46 mounted rigidly with the field windings. A pair of springs 47 and 48 are positioned to react between armature 43 and bracket means d5 and 46, which springs serve both as spacers and as cushioning means Afor the armature in the course f 3 of axial shaft movements derived from alternate energization of the tiel-d windings 41 and 42.

Mot-or shaft 44 carries a propeller type fan 50 at one end and a -like fan 51 at the other end. Disc 52 comprising the damper element is axially aligned with shaft 44 and is spaced trom ian S0 along the shaft. Similarly, a disc 53 is carried by sha-ft 44 and spaced from fan 51. Rotation of a fan and its adjacently disposed disc or damper element is accompanied by `substantially radial air discharge from the propeller type fan, which discharge has been 4found effective to create the desired air circulation to be more fully described later in the disclosure.

In one of the armature or rotor positions, vfor example the one shown in FIGURES l, 3, and 4, rotor 43v and shaft 44 are so positioned as to be rotated by motor eld winding 42, and to dispose the fran Si) within evaporator or plenum chamber 16. Concurrent with the foregoing, the disc 52 is disposed substantially within the opening 32 in wall 25 adjacent :freezer compartment 14. In this same shaft position, the right-hand fan 51 is disposed within food compartment and disc 53 is positioned clear of the right-hand opening 30.

`In the' above described positions of `fans 5d and 51, bot-h will operate, with fan 50 assisting in agitating of the air within plenum chamber 16 and causing it to How more vigorously, as shown by the arrows, over the evaporator to impr-ove the air-to-evaporator heat transfer with the chamber. A -deector 2b is disposed Iadjacent opening 31 and substantially prevents Iflow of .agitated air into the freezer compartment when the opening 32 is covered by disc 52. Fan 51 moves air `from evaporator compartment or plenum chamber 16 into -food compartment e15, which air then ows from the latter compartment through the upper opening 26 and back into the plenum chamber, which air ilow also is indicated generally by arrows. Little, if any, iiow takes place between plenum chamber 16 and lfreezer compartment 14, since disc lS2 by closing off opening 32 precludes any air flow therethrough and little air if any can flow through the ybailie opening 31 due to the lack of sufficient head pressure.

As seen in FIGURE 2, when the fan motor shaft 44 is displaced to its left-hand position, air is caused .to ow between tfreezer compartment .14 and plenum chamber 16 as indicated by the arrows. A deflector 219 prevents outow of agitated air through opening 26 when opening is covered by disc 53.

Control means for effecting the above fan operation, as well as for controlling operation of the compressor for either -defrosting or refrigerating periods, is best seen in FIGURES 5 through 5C. Compressor 21 is connected in series electrical circuit with line L and the single-pole single-throw switch 54 operated by temperature sensing bellows and bulb arrangement 55 of thermostatic control 34. Also connected in series circuitry with line L are each of the ield windings 41 and 42 of motor 40 and a single-pole double-throw switch 56 operated by second bellows and bulb arrangement 69 of thermostatic control 35.

For a complete understanding of the operation of the apparatus, and for the sake of illustration, the following temperatures will be assumed to be prevailing at the locations indicated, in a 90 F. ambient atmosphere:

F. Freezer compartment temperature 13 Food compartment temperature 38 Evaporator temperature compressor thermostat switch 54 is closed and the fan switch `56 positioned to energize motor iield winding 41 4 thereby to cause `fan 51 to .function -for the cooling of food compartment 15 as hereinabove described. The circuit will remain energized in accordance with the shoviing of FIGURE 5 until the following exemplary conditions are reached:

F. Freezer compartment temperature 15 Food compartment temperature 35 Evaporator temperature 8 In the embodiment here under consideration, the controls are so calibrated that when the evaporator temperature reaches the above indicated 8 F., compressor switch 54 remains closed and fan switch 56 moves to the position shown in FIGURE 5A, to cool freezer compartment 14. This circuit is maintained until the temperatures reach the values indica-ted below, when thermostat switch 54 moves to provide the circuit shown in FIGURE 5B, in which the compressor is deenergized and the freezer compartment air circulating fan 50 becomes operational:

F. Freezer compartment temperature 5 Food compartment temperature 39 Evaporator temperature 0 The unit continues to be energized according to the showing of FIGURE 5B until the temperatures are, for example, as follows, at which time switch 56 moves to the position shown in FIGURE 5C to deactivate freezer fan 5t) and make the `food comp-artment `fan 51 operational:

F. yFreezer compartment temperature 11 Food compartment temperature 42 .Evaporator temperature 8 The circuit shown in FIGURE 5C then exists until the evaporator has defrosted, by virtue of deenergization of the compressor and movement of above-freezing temperature (42 F.) air in heat exchange relation with the evaporator'. When the evaporator temperature reaches 3S F., the circuit will revert to .that shown in FIGURE 5, thereby starting motor compressor 21 and the next reirigerating or cooling period.

As will now be apparent, the present invention provides not only an improved air moving means, but also simple and effective means for defrosting the evaporator of a refrigerator merely by circulating relatively warm air from the food compartment in high heat exchange relation with the idle evaporator element, which heat exchange also cools the food compartment. In such operation, the evaporator is readily defrosted on every cycle.

yI claim:

1. In air moving apparatus, Ythe combination compris ing: |a pair of chambers; means defining a port providing lair flow communication between said chamber-s; motor means including a rotatable shaft, @said shaft being axially movable between a pair of positions in response to energization and deenergization 4of said motor means; fan means carried by :said shaft l.and disposed for movement toward and away from said port means in response to axial movements of said shaft; damper means movable with said -tan means .away from .and toward said port means to open :and close the same, the construction and arrangement being such that when `said fan means is moved toward said port means said damper means is so positioned as 'to open said port means to permit flow of air therethrough, and when said fan means is moved away from said port means, `said damper means is so positioned as to close said port means to prevent ilow of therethrough. 2. Apparatus according to claim 1 and characterized in that one of said chambers comprises an evaporator compartment of a refrigerator and the other of said chambers comprises -a storage compartment of a refrigerator.

3. In :air moving apparatus, the `combination comprising: a pair of chambers; means deiining a port providing -air diow communication between said chambers; motor means including a rotatable shaft; fan means carried by said shaft 'and disposed for rotation :therewith `and adapted for movement :along the axis of `said shaft between a pai-r of positions adjacent said port mean-s to provide for movement of :air from one of said chambers, through said port means, and to `the .other of said chambers; and damper means movable to open and to close said port means, said damper means being operable by said fan means to open said port means in one of said positions ot rotation of said fan means, and being operable by said lfan means to close said port means in another of said positions of rotation of said fan means.

4. Apparatus according to claim 3 and characterized in that said rotatable shaft lis disposed and :adapted -for axial movements to provide movements of said fan means between said pair of positions, said shaft being 'operatively associated with said damper means to open and close said port means upon the recited yaxial movements of said shaft.

5. IIn air moving apparatus: an electric motor comprising a pair of adjacently disposed axially aligned tield windings yand single rotor means adapted for selective drive by one of said iield windings in response to energization of the latter to the exclusion of the other winding, said rotor lfurther being laxially movable by the magnetic iield .of the energized one `of said windings; rotatable shaft means `disposed and adapted It-o be driven with said rotor means, said shaft means being mounted for axial movements with said rotor means as itis moved into the iield of the one of said windings by which it is to be rotated; fan blade means carried by said shaft means; damper plate means Idisposed :adjacent said fan blade means and adapted for movements with said shaft means as it is caused to be moved axially to control air discharged by said fan blade means; and control means disposed and adapted selectively to energize one of said eld windings while Ideenergizing the other.

6. lIn Iair moving apparatus: an electric motor comprising a pair of vadjacently disposed axially aligned field windings and single rotor means adapted for selective drive by one of said iield windings in response to energization of the latter to the exclu-sion of the other winding, said rotor means further being axially movable by the magnetic field of the energized one of said windings; fan blade means rotatably vand axially movable with said rotor means; damper plate means disposed .adjacent said fan means and 'adapted for movements with said rotor means as it is caused to be moved axially to control air discharged by said fan blade means; and control means disposed and adapted selectively to energize one of said eld windings while deenergizing the other.

7. In air moving apparatus, an electric motor comprising a pair of adjacently disposed axially aligned iield windings and single rotor means :adapted for selective drive by either of said iield windings in response to energization ofthe latter to the exclusion of the other winding, said rotor means further being axially movable by the magnetic ield of the energized yone of said field windings, fan blade means rotatably and axially movable with said rotor means, .air pasage means cooperably disposed with respect to said fan blade ymeans and adapted for flow therethrough of air discharged by the fan blade means when it has been molved axially, and control means disposed `and adapted selectively to energize either of said eld windings while `deenergizing the other.

8. In motor driven :air moving means, means defining an air passage, an electric motor including rotor and stator elements, a fan carried by said rotor element, and means providing for .axial movement of said fan-carrying rotor element when the motor is energized, said Vfan and said air pass-age being so constructed and cooperably disposed that the fan is operative to move air through the said passage only when so axially moved by the rotor.

9. In motor driven air moving means, means dening a pair yof air passages, an electric motor including rotor fand stator elements, a pair of fans, each supported :at =a corresponding end of said rotor element and each cooperatively disposed with respect to a corresponding one of said air passa-ges, means provi-ding for axial movements of said fan-carrying rot-or when the motor is energized, the construction and `arrangement being such that one fan, under one axial position of the rotor, is effective to move lair through its corresponding air passage while the other fan is ineffective to move lair through its corresponding -air passage.

l0. In air moving apparatus, the combination comprising: a plurality of chambers; means defining port means providing air tlow communication between said chambers; motor means including a rotatable shaft, said shaft being axially movable between a pair of positions in response to energization and deenergization of said motor means; fan means carried by said shaft and disposed for movement toward and away from said port means in response to axial movements of said shaft, said fan means being so constructed and cooperably disposed as respects said port means that when it is moved toward said port means it is operative to cause tiow of air through said port means, and when said fan means is moved away from said port means it is substantially inoperative to cause ow of air through said port means.

ll. Apparatus according to claim 10, and further including baflie means associated with said fan means and movable thereby to a position in which it closes said port means in response to axial movement of said shaft means to one of its pair of positions.

12. Refrigerator apparatus comprising: a lower temperature compartment; an above-freezing, higher ternperature compartment; means defining a plenum chamber; defrostable cooling means disposed Within said charnber, said cooling means being cyclically deenergizable in the normal function thereof to accommodate defrosting of the same; a pair of apertures for providing flow of air between said plenum chamber and each said compartment; and air moving means including a pair of fans, each disposed adjacent a corresponding one of said apertures and mounted for axial movement between a pair of positions toward and away from said apertures, one of said fans when positioned toward the aperture communicating with the higher temperature compartment being operable to etiect llow of air solely from said higher temperature compartment over said cooling means to defrost the same when the latter is deenergized, the other of said fans then being positioned away from its corresponding aperture and serving solely to agitate air within the plenum chamber whereby to increase the heat exchange between the higher temperature air and the cooling means.

13. Apparatus according to claim l1, and further including damper means mounted for operation by said fans and disposed and adapted to open one and close the other of said apertures as said fans are positioned to effect the recited air How.

14. For use with impellers, and like apparatus: an electric motor comprising a pair of adjacently disposed axially aligned iield windings and single rotor means adapted for selective drive by either of said iield windings in response to energization of the latter to the exclusion of the other winding, said rotor means further being axially movable by the magnetic lield of the energized field winding; and control means disposed and adapted selectively to energize one of said eld windings while deenergizing the other.

l5. For use with impellers, and like apparatus: an electric motor comprising a pair of adjacently disposed axially aligned field windings and single rotor means adapted for selective drive by either of said field windings of the other winding, said rotor further being axially `movableby the magnetic eld'of the energized winding;

rotatable shaft means disposed and adapted to be driven with said rotor means, said shaft means being mounted for axial movements with said rotor means as it is moved into the eld Vof the one of said windings by which it is to be rotatedg'and control means disposed and adapted selectively to energize one ofsaid field windings while deenergizing the other.

16. In refrigerator apparatus, a lower temperature compartment, a'higher temperature compartment, means deliuing a plenum chamber, defrostable cooling means disposed within said chamber and being cyclically deenergizable in the normal function thereof, and air moving means operable either to cause air tol flow between one of saidr compartments and said plenum chamber for heat exchange with said cooling means to cool such compartment or, when the cooling means is deenergized, to ef- `fect flow of air solely from said higher temperature compartment over said cooling means tov defrost the same, said air moving means comprising: means dening a pair of apertures for providing flow of air between said plenum chamber and said compartment; fan means including a pair of fans each disposed adjacent a corresponding one of said apertures and mounted for axial movement between a pair of positions; and dampery plate'meansmovable with each said fan to open and to close the aperture associated therewith in response to axial movement of said fans, whereby the recited selective How between said chamber and a compartment is elfected.

Mann Oct. 17, 1961 Mann Oct. 17, 1961 

8. IN MOTOR DRIVEN AIR MOVING MEANS, MEANS DEFINING AN AIR PASSAGE, AN ELECTRIC MOTOR INCLUDING ROTOR AND STATOR ELEMENTS, A FAN CARRIED BY SAID ROTOR ELEMENT, AND MEANS PROVIDING FOR AXIAL MOVEMENT OF SAID FAN-CARRYING ROTOR ELEMENT WHEN THE MOTOR IS ENERGIZED, SAID FAN 